Copying machine having early copy paper feed in multiple copy mode of operation

ABSTRACT

An electrostatic copying machine of the type disclosed in Van Auken et al. application Ser. No. 30,923, filed on Apr. 22, 1970 now U.S. Pat. No. 3,677,635 and entitled &#39;&#39;&#39;&#39;Copying Machine System&#39;&#39;&#39;&#39;. The Van Auken et al. machine includes a clutch and cam arrangement for controlling the early feed of copy paper while the original is being reverse transported in the multiple copy mode, and allows multiple copies of an original to be made very rapidly. The shortcomings of the clutch and cam arrangement are eliminated in the present invention by the substitution of an electronic circuit. A further advantage of the electronic circuit is that it permits a relatively simple adjustment to be made for achieving perfect registration between the original and each copy sheet.

United States Patent [1 1 Nordine [5 4] COPYING MACHINE HAVING EARLY COPY PAPER FEED IN MULTIPLE COPY MODE OF OPERATION [75] Inventor: Richard D. Not-dine, Oakland Park,

Fla.

[73] Assignee: Copystatics Manufacturing Corporation, Miami Lakes, Fla. [22] Filed: Dec. 1, 1970 [21] Appl. No; 94,041

[52] US. Cl. ..355/5l, 355/8, 355/14,

[51] Int. Cl. ..G03b 27/42 58] Field of Search ..,...355 /8, 11,13, 14, 50,51,

[56] g References Cited UNITED STATES PATENTS 3,604,796 9/1971 Ogawa....' ..'..355/i4 1/1969 Robertson et al.; ..355/8 1 Jan. 16,1973

3,575,503 7 4/1971 Van A'uken ..355/8 Primary Examiner-Samuel S. Matthews Assistant ExaminerRussell B. Adams, Jr. Attorney-Amster & Rothstein s71 ABSTRACT An electrostatic copying machine of the type disclosed in Van Auken et al. application Ser. No. 30,923, filed on Apr. 22, 1970 now US. Pat. No. 3,677,635 and entitled Copying Machine System. The Van Auken et al. machine includes a clutch and cam arrangement for controlling the early feed of copy paper while the original is being reverse transported in the multiple copy mode, and allows multiple copies of an original to be made-very rapidly. The shortcomings of the clutch and cam arrangement are eliminated in the present invention by the substitution of an electronic circuit. A further advantage of the electronic circuit is that it permits a relatively simple adjustment to be made for achieving perfect registration between th original and each copy sheet.

33' Claims, 12 Drawing Figures PATENTEDJm s 1915 SHEET 1 [1F 7 INVENTOR RICHARD WORD/NE flan/t1"! Ronni; ATTORNEYS PMENTEUJM 1s 19?:

SHEET 2 OF 7.

PATENTEUJAH I6 1915 SHEET 3 [)F 7 PATENTED JAN 16 I973 SHEET [1F 7 FIGS.

FIG. 6.

Q g. r

PATENTEUJAN 16 1975 3.711, 198 SHEET 5 [1F 7 r I 4: NASQQSQ U mix V/ 3&3 kxw w k v PATENTEDJAH 16 1915 SHEET 7 BF 7 COPYING MACHINE HAVING EARLY COPY PAPER FEED IN MULTIPLE COPY MODE OF OPERATION This invention relates to copying machines, and more particularly to a copying machine in which an electronic circuit controls the early feed of copy paper during the multiple copy mode.

In Van Auken et al. application, Ser. No. 30,923, filed on Apr. 22, 1970 now U.S. Pat. No. 3,677,635 and entitled Copying Machine System" (hereinafter referred to as the Van Auken et al. application), there is disclosed a copying machine system which in cludes a copying machine and various attachments therefor. The copying machine is designed to cooperate differently with each of the attachments in order to operate in a different mode. The first attachment is a letter bridge which when placed on the machine allows copies to be made of sheet documents (letters, etc.). The second attachment is a book copier unit which includes a glass platen placed on top series detects the trailing edge of the original after the original has completely cleared the scanning window in the forward direction. When the trailing edge is sensed,

clutch is operated to cause a cam to be driven by the of the machine. With this attachment, the machine functions as a book-copier type machine. The third attachment is a microfilm. scanner which when placed on top of the copying machine allows copies to be made from microfilm originals. The present invention is concerned primarily with the resulting system when the letter bridge is placed on the machine.

As will be described below, with the letter bridge in place on the copying'machine, there is a cam in the machine which is driven by a chain to control the early start of copy paper feed. When multiple copies of an original are to be made, the original is shuttled back and forth past the scanning window. Rather than to return the original to the starting point of the first cycle and to then start moving it forward again together with movement of a newcopy sheet, the original is returned only. until it just celars the scanning window. Im-

mediately, it then starts to move once again in the forward direction. This requires that the copy paper have moved to the front edge of the exposure window by the time the original has just cleared the scanning window in the reverse direction. The early start of the copy feed (while the original is being reverse transported) is controlled by a clutch and cam arrangement in the machine, the clutch and cam being operative only when the system is operated in the latter copying mode. However, as is known in the art, there'are many disadvantages of using clutches; for example, more service calls are required to replace a typical clutch than are required to fix an electronic circuit. 7

It is a general object of my invention to provide a copying machine of the type disclosed in the Van Auken et al. application (which is hereby incorporated by reference) which includes an electronic circuit for controlling the early feed of copying paper in the multiple copy mode.

It is another object of my invention to provide such an electronic circuit which further permits simple correction of errors in the registration of the original and copy sheets.

The Van Auken et'al. letter bridge includes three sensors. The first detects when an original is first inserted in the machine. The second and third are disposed just before and immediately after the scanning window in the path of movement of the original document. In the multiple copy mode, the third sensor in the drive chain system which controls movement of the original. When the third sensor detects the trailing edge of the original, the original is moved in the reverse direction by causing the drive chain to move in the reverse direction. The cam, which is driven by the chain and until this time has moved in the forward direction, now starts to move in the reverse direction. But when it moves in the reverse direction, it controls the closing of a pair of contacts some time before it returns to its original position, that is, some time before the leading edge of the original has moved in the reverse direction and has reached the third sensor. When the contacts close, the copy paper feed starts. The cam is arranged to close the contacts as it is moved in its reverse direction at such a time that the leading edge of the copy sheet reaches the front edge of the exposure window just when the original has cleared the scanning window and is ready to move in the forward direction once again.

In accordance with the principles of my invention, the clutch and cam are omitted and it is the detection by the third sensor of the leading edge of the original as it is moved in the reverse direction that initiates the copy paper feed. Thus no additional sensing elements, clutches or cams are necessary to start the early feed of 1 copy paper. However, inasmuch as in the Van Auken et ,al. machine for proper registration the copypaper feed should begin before the leading edge of the original has reached the rear edge of the scanning window as itv moves in the reverse direction, itis apparent that there is a delay" in the start of the copy paper feed. The delay is only a fraction of a second but there is a noticeable registration error by the time the original 7 has just cleared the scanning window in the reverse direction and is ready to move once again in the forward direction, the copy sheet has yet reached the front edge of the exposure window.

In order to use the third sensor to control the start of the copy paper feed, without requiring an additional mechanism for starting the copy paper feed a bit earlier, what is done to delay the change from the reverse movement of the original to the forward movement of the original. In the Van Auken et al. machine, when the second sensor (in front of the scanning window) detects the leading edge of the original as it moves in the reverse direction, the original transport system in the machine changes direction so that the original is immediately moved forward. In accordance with the principles of my invention, an electronic delay circuit is provided so that the direction of the original drive chain does not switch until a fraction of a second after the second sensor detects the leading edge of the original as it moves in the reverse direction-Thus the original is actually transported slightly farther in the reverse direction before it starts to move forward once .again. The additional travel of the original, in the reverse direction and then forward again until the leadingedge of the original reaches the scanning window, requires a time interval which just equals the interval between the time that the cam-controlled contacts in the Van Auken et al. machine close and the time that the third sensor detects the leading edge of the original as it is moved in the reverse direction. Thus simply by providing an electronic delay circuit, it is possible to use'the third sensor to control the start of copy paper feedwithout any need for additional sensing elements, clutches or cams.

This arrangement necessarily results in a slightly longer time being required to make each copybut inasmuch as the time involved is only a fraction of second, it is of almost no concern. It is more than compensated for by the increased reliability of the system.

' elsewhere in'the machine.

. It is a feature of my invention to utilize the third sensor at the rear edge of the scanning window to control the early start of copy paper feed when a copying machine of the Van Auken et al. type is operated in the multiple copy mode.

It isanother feature of my invention to provide an adjustable delay circuit for controlling, together with the second sensor adjacent to the front edge of the scanning window, the exact time when the original switches from the reverse direction to the forward direction in the multiple copy mode so that perfect registration between the original and the copy sheet can be effected simply.

Further objects, features and advantages of my invention will become apparent upon consideration of FIG. 8 depicts the modifications to the Van Auken et al. control circuit of FIG. 3 which are required in acco'rdance with the principles of the present invention;

FIG. 9 is the same as FIG. 13 in the Van Auken et al. application and illustrates the pin connections in the connector of the letter bridgedisclosed in the Van Auken et al. application; I

'FIG. 10 is the same as FIG. 14 in the Van Auken et al. application and depicts the circuit which results in the Van Auken et al. machine when the. connector of the letter bridge is'mated with the connector of the copying machine (which connector has various pins coupled to numerous points in the circuit of FIG. 3);

FIG. 11 illustrates the pin connections in the connector of the letter bridge which can be used in accordance with the principles of my invention; and

FIG. 12 depicts the circuit which results when the connector (FIG. 11) of the letter bridge is mated with the connector of the copying machine to couple the bridge to the control circuit of FIG. 8.

Although the Van Auken et al. copying machine system exhibits an early copy paper feed when. the letter bridge is utilized, the concept of early copy paper feed is disclosed in the earlier Van Auken et'al. application Ser. No...725,390 now U.S. Pat. No. 3,575,303,

FIG. 1 of which is reproduced as FIG. 1 in both thewhose operation is very similar to the operation of the the following detailed description in conjunction with V f the drawing, in which:

FIGS. 1-7' are the same as the respective figures in i the Van Auken et al. application, with FIG. I being the'same as FIG. 1 in an earlier Van Auken et al. application Ser. No. 725,390, filed on Apr. 30, 1968 now U.S. Pat. No. 3,575,503 and entitled Copying Machine System, and depicting the general layout of the various elements included in the copyin machine of my invention;

FIG. 2 being a side viewof the copying machine (with the side cover removed) and showing the chain for driving various elements in the machine;

FIG. 3 depicting schematically the control circuit of the Van Aukenet al. copying machine, various points in the circuit being connected-to respective pins in a connector ontop' ofthe machine described in detail in of FIG. 4

together with various dimensions thereof;

machineof FIG. 1. To understand the present invention, it will be necessary mfirstreview the operation of the machine of FIG. I' (the earlier Van Auken et al. application), and the operation of the copying machine system disclosed in the later-filed Van Auken etal. ap-

plication. n 7

GENERAL DESCRIPTION OF VAN AUKEN ET AL.

. MACHINE OPERATION The copy paper used in the machineis electrophotographic in nature. It has the ability toretain an electric charge placed on its photoconductive coating by anv electrostatic tield.'The coating can be discharged by the application of light. Typically, copy paper roll'l33 of v FIG. 1 consists of a base paper with'photoc onductive 'As the'le'ading edge of copy paper -roll 33 passes I through rollers 35, 36, 39, 40 and '41, 42, the paper passes'through the corona shields 43, 44 which house two sets of very fine wire elements (not shown) across which. is placed a high DC voltage supply. The negative wire elements are contained within shield 44 while the positive wire elements'are contained within shield 43. The shields aid in establishing thecorona field.

As the copy paper passes through the two sets of oppositely charged wire elements, a uniform negative charge is applied to the photoconductive coating on the surface facing shield 44. A uniform positive charge is placed onthe surface of the coating facing shield 43. The charges placed on the surfaces of the copy paper will be retained for a reasonable length of time provided it is not exposed to any light. When light strikes the photoconductive coating, the zinc oxide particles which are exposed become conductive, neutralizing the negative and positive charges in the exposed areas.

As the copy paper passes the exposure window consisting of a glassless window strung with monofilament 64 and pressure member 23, the photoconductive coating is exposed in accordance with dark and light areas on the original to be copied. Rotary knife 38 cuts a copy sheet from the roll such that the cut sheet is the same length as the original to be copied. When knife 38 operates, the copy roll paper feed stops, although the cut copy sheet continues to move past the exposure window to trough 47 in the developing section of the machine.

The original document 12 is fed into the machine between rollers 9, 16 which turn to move the original in the direction shown (from the right end of the machine in FIG. 1 to the left end). As the original passes the scanning window, on top of glass plate 22, light from two exposure lamps (shown in phantom in FIG. 1) within reflector 25 is reflected from the light image areas on the original along the dotted arrows 27 as shown. The light passes through lens system 28, assembly 30 and window 64 to expose the copy paper. The copy paper feed is controlled such that the leading edge of the copy sheet within the exposure window is in optical synchronization with the leading edge of the original'within the scanning window. The copy paper retains a negative charge in those areas corresponding to dark (image) areas-on the original. The non-image areas on the original reflect a great deal of light to the surface of the copy paper causing the neutralization of the charged areas corresponding to the non-image areas on the original.

The copy sheet is then fed to trough 47. As shown in the drawing, the forward end of the copy paper has just entered the trough. The copy sheet continues to travel along path 46 until the copy sheet is ejected from the machine. In trough 47 there is-adeveloper solution consisting of charged toner particles which are attracted to the negatively charged image areas on the copy paper. The attracted toner particles are impregnated and fixed to the copy paper coating by a system of squeegee rollers and forced hot air drying.

The machine includes two basic systems of feed rollers or paper transport rollers. One system is kept constantly rotating by a series of sprockets and drive chains, while the second system is clutch-controlled so that it operates only whenone of two clutches is engaged. FIG 2, to be described below, shows these systems in the machine.

When original document 12 is inserted between pick-up rollers 9, 16 the original is transported to the left in FIG. 1. As the leading edge of the original emerges from rollers 9, 16, it actuates photocell switch 13. Each of photocell switches 13, 14, is provided with a respective light source 21, 20, 19. When the leading edge of the original passes between a light source and its respectivephotocell switch, the change in state is registered and used to control the machine operation. When switch 13 first operates, copy paper roller clutch K-l2 (FIG. 2) is energized to cause copy paper insert rollers 35, 36 to rotate. These rollers pull the forward edge of the copy roll to direct the copy paper through the corona unit. The other rollers along the copy paper path continuously operate. Initially, the forward edge of the copy paper is adjacent to blade 37 and knife 38. Thus, although the rollers following the knife along the copy paper path rotate continuously there is no copy sheet to be transported through the machine. But once rollers 35, 36 start operating, copy paper is drawn from the roll into the copy paper transport system. The corona unit within shields 43, 44 charges the surfaces of the copy paper. The original and the copy paper are synchronized in their movements. The distance along the copy paper path from the knife to the intersection of the optical axis with the exposure window equals the distance from photocell switch 13 to the intersection of the optical axis with the scanning window. Since the rollers along the original and copy paths move the original and the copy paper at the same speed, and since the copy paper starts to move past the knife under control of rollers 35, 36 just when the forward edge of the original is adjacent photocell switch 13, it is seen that the original and copy paper are in optical synchronization with each other during the scanning process.

As the trailing edge of the original passes photocell switch 13, the copy paper roller clutch K-l2 is disengaged. Rollers 35, 36 stop turning and copy roll 33 remains stationary. At the same time a knife solenoid (not shown on FIGS. 1 and 2) is energized to cause rotary knife 38 to cut the copy paper to the exact length of the original. The cut sheet continues to be transported by the copy paper transport system through developer-trough 47. intensifier drum 48 is constantly turned in the direction shown. (It is possible to turn it in the opposite direction, and at various speeds'as well.) This insures that the copy paper is guided through the developing trough. The developer solution itself is contained in tank 57 which can be pulled out of the machine by handle 58. A pumping system (not shown) pumps the developer upward into trough 47.

The copy sheet then passes under deflector 56 toward the nip of squeegee rollers 53, 54. The squeegee rollers remove the excess liquid dispersant from the copy paper andto some slight degree also imbed theattracted toner particles into the zinc oxide coated surface of the copy paper. Wiper 52 wipes metal squeegee roller 53 to prevent tracking back" or offsetting of a previous image, just as wiper 5-1 wipes intensifier drum 48. The copy sheet is then forced down by the circulat ing air under drier lamp 59 onto belt 61 which moves continuously around rollers 62, 63, roller 62 being turned by the constantly rotating chain drive. The copy sheet is finally passed between belt 61 and plastic idler rollers 55, several of which may be included on the same shaft. These rollers slightly crease the copy paper so that it will stack properly in the copy receiving tray (not shown).

Blowers 23, 24 force air (shown by arrows 26) through the machine as is well known in the art, for example, to dissipate the heat generated by the exposure lamps. A series of guides 32 are provided for properly directing the air.

Shutter 31 can be moved up and down from outside the machine (not shown); the lower the right end of the shutter, the larger the opening and the greater the exposure. The units shown symbolically on FIG. 1 are generally of types well known in the art andfor the purpose of the present invention need not be gone into in any greater detail. A machine constructed in accordance with the principles of my invention includes many mechanisms, controls and indicators, not shown in the drawing. For example, various indicator lights ple copy selector dial 107 (see also FIG. This dial is marked in equal graduations numerically representing the number of copies desired. The selector dial can be reset at any time during machine operation providing for maximum flexibility. If the selector dial is allowed to remain in the normal position (single copy mode) shown in FIG. 5, the machine will produce only one copy for each original inserted into it. Any other position will provide the number of copies as indicated by the selector dial setting.

In the multiple copy mode, during the first cycle the original is scanned in the usual manner. Before it has travelled far enough to be released by the last set of rollers 7, 18, the trailing edge of the original actuates photocell switch 15. This causes the original transport roller system to reverse and return the original, at a speed greater than the forward speed, to the I right toward "the normal insertion point. When the leading edge of the original clears photocell '14, the original transportroller system is again normalized and transports the'original to the left past the scanning window where it is scanned a second time. (All references hereinto leading and-trailing edges of the original are made respectively'to the left edge of the original and direction. When the original starts to move in the reverse direction, cam 106 starts restoring in-the clockwise direction. The cam is fully restored when the leading edge of the original passes photocell in the 1 reverse direction. But during the clockwise movementof cam 106, some time prior to its full restoration,

' switch SW-Q is operated. The operation of the switch starts the copy paper feed. The leading edge of the original must yet travel back past photocell l5 (switch SW-Q operates while the leading edge of the original is still to the left of photocell 15 in FIG. 1 and the scanning window to photocell 14. The leading edge of down, to the normal single copy mode position. The

dial isdecremented one position for each copy made by the machine. When all copies have been made except the last, the selector diaI'is fully 'decremented to the single copy mode position, at which time the machine will original receiving tray.

To speed up'the multiple copy operation, the original is returned only so far as to allow its leading edge to clear the forward" end of the scanning window. Since the original immediately'starts its forward movement, it isnecessary for the leading edge of the copy sheet to be at the forward end of the exposure window by this time, i.e the copy feed must start while the original is still being moved in the'reverse direction. In the single copy mode, the copy feed starts when photocell l3 detects the leading edge of the original. But in the multiple copy mode, except'during thefirst forward feed of the produce one more copy and deposit the original in the the copy paper must travel from the knife tothe forward end of .the exposure window during the same time interval. The original reverse feed rateis greater than the copy feed rate. To assure proper registration of the original and copy within the scanning and exposure windows it is only necessary to have cam 106 operate switch SW-Q at a point during the reverse'movement of the original where the ratio of the distance of the leading edge of the original from photocell 14 to the distance between the knife and that point in the copy sheet pathoflmovement where the copy sheet becomes synchronized to movement of the original is equal to the ratio of the original reverse feed rate to the copy feed rate. In this way the leading edge of the original will reach photocell'l4 just when theleadingedge of the copy sheet reaches the exposure window. I

As soon as photocell l4 detects the leading edge of the original, the original starts moving in the forward direction at the same'speed'as the copy paper is moving. It is still" necessary to cut the copy sheet. This is easily accomplished. The positions of the original and copy paper are the same as though the machine were operating in the single copy mode. Consequently, when photocell 13 detects the trailing edge of the original, it

actuates the cutting mechanism and inhibits further feed from the copy paper roll. The length of the cut copy sheet during each cycle in the multiple copy mode is'thus the same as that of the original.

General Description of Van Auken et and Copy Transport Systems direction by sprockets 71. This chain turns varioussprockets, including tension adjustment idler sprocket 123 and the sprockets coupled to rollers 42, 50, 53 and 62. These four rollersturn continuously. to move the.

copy paper. The fifth roller which is continuously turned in the-path of the copy paper is roller 40, coupled to a sprocket driven by drive cha'in 73. Chain 73, likechain 74, is drivenbysprockets 71 as Iongas the main; power switch is energized. Chain 74 drives sprocket 79 in the counterclockwise direction and drives sprocket 76 in the clockwise direction. Sprocket 76 rotates at a greater speed than that-of sprocket 79 because of its smallerdiameter. I I 1 Chain is the original transport drive chain. 'It is driven indirectly by main drive chain 74 through an electrical clutch systempwhenforward clutch K-9 is energized, sprockets 78 and 79 are clutched together and sprocket 78 moves with continuously rotating sprocket 79. Drive chain 75 moves in the'forward (F) al. Originaldirection, and since the diameter of sprockets78 and 79 are the same, chain 75 moves at the same speed as chain 74. Since the transport rollers have the same.

forward and reversing process continues as long as the clockwise, rollers 16, 17 and 18 move in the reverse direction (opposite to that shown in FIG. 1) to return the leading edge of the original to the forward end of the scanning window. When this point is reached, the control circuits again change the driving direction of chain 75 by de-energizing reverse clutch K-8 and energizing forward clutch K-9.

Although chain 73 continuously drives the sprocket coupled to roller 40, as well as the three gears following i it and terminating in gear 80, roller 35 does not rotate continuously. This is the roller which starts the copy paper feed. Only when clutch K-12 is operated is roller 35 coupled to gear 80. At this time copy paper feed begins.

The drive system is shown only schematically in FIG. 2, since the basic elements of such a drive system are well known. For example, it is understood that chain 74 can be used to drive any other elements whichvmus t be driven in the machine. The important thing to note in FIG. 2 is the use, of three clutches in connection with sprocket pairs 78, 79 and 76, 77, and gear 80. The first clutch controls the forward movement of the original document. The second clutch controls the reverse movement of thevoriginal document at a faster speed. The third clutch control copy paper feed.

In the original transport system, rollers 16, 9 serve as the original input rollers, rollers 17, 8 serve as the scanner input rollers, and rollers 18,7 serve as the original exit rollers. As described above, rollers 16, 17 and 18 are driven by chain 75 in either direction. Rollers 7, 8 and 9 are contained in bridge assembly 11 and are in friction contact with their respective lower rollers when bridge 11 is placed on the machine. The bridge is removable so that in the event of an original jam, it can be corrected with little difficulty. Photocell switches 13, 14 and 15 contained in bridge 11 are connected to the rest of the machine by contacts on bridge 11. The bridge also includes a pressure plate (not shown) for bearing against the original on top. of scanning glass 22. The spacing between the pressure plate and scanning glass 22 is several paper thicknesses.

An'original collecting tray (not shown) is provided at the left end of the machine of FIG. 1 for collecting successive originals as they are fed through the machine. During multiple copying, the original is scanned in the forward direction in the usual manner, but before it isreleased by exit rollers 7, 18, all three pairs of transport rollers are automatically reversed and the original is returned at high speed in the reverse direction. The control circuit to be described below prevents a copy from being made while the original is being reversed. The original continues to be transported in the reverse direction until the leading edge is to the right of scanning window 22 at which time the control circuit again causes the original to be transported in the forward direction to be scanned again. Photocells 14 and 15 are disposed at each end of the scanning glass and serve various functions to be described below. Photocell 13 serves to control the length of the'cut copy sheet as well as the copy paper feed.

Copy paper roll 33 is mounted on copy paper roll shaft 34. Although not shown, as is known in the art,

provision is made for placing new copy paper rolls on the shaft as they are used up.

The operations of the original transport system during the single and multiple copy modes are considerably different. However, with respect to the copy transport system the operation is the same. Rollers 35, 36 and knife 38 control successive feedings of copy sheets into the copy transport system.

Copying Machine Circuit of Van Auken et al. System FIGS. 3-7' 1 FIG. 3 depicts schematically the control circuit of the copying machine which includes. the various elements shown in FIG. 1, without bridge 11. As described in the Van Auken et al. application, any of several different attachments may be placed on top of the copying machine. The top of the copying machine includes three rollers, 16, 17, 18 (FIG. 1) a scanning window 22, and three exciter lamps 19, 20, 21. Also, at the top of the copying machine, there is an electrical connector having a number of pins coupled to various points in the circuit of FIG. 3. The various circles shown in the circuit of FIG. 3 represent the pins, with the number or letter in each circle representing the-pin number or letter. The pins are identified by the numbers l-l 5 and the letters A-H, J-L, N, P and S. (No connection is made to pin G, an extra pin".)

It is difficult to understand the operation of the overall circuit in any one of the three possible modes with reference to FIG. 3. Although the electrical circuit of each of the three attachments, as well as thepin connections in each of the attachments, are shown in separate figures, it is far easier to understand the operation of the machine in any particular mode by redrawing the circuit which results when each of the attachments is placed on the machine. The redrawn" circuits are shown in the Van Auken et al. application and the letter bridge redrawn circuit will be con- 1 sidered below. Furthermore, to simplify matters, the

redrawn circuits have omitted from them all of the elements which do not function in the particular mode. For example, switches SlA, SIB, S2A, 83A and 801 are included on the top of the machine. However, these switches are closed only by the book copier platen, and accordingly do not enter into the system operation in the letter copier and microfilm reader modes. For this reason, the redrawn circuit for the letter bridge, to be considered below, does not depict these switches.

As another example, consider pin E on FIG. 3. This pin is connected to positive potential bus 115. Referring to FIG. 9 (identical to FIG. 13 in the Van Auken et al. application)-which shows the electrical connections within the letter copier bridge (as will be described more fully below), the letter copier bridge includes a circuit board which interconnects pins Eand F on the copying machine. Referring back to FIG. 3, his seen that pin F is connected to both switch SQl and switch SW-D. Thus, in the letter copier mode, the positive potential bus 115 is connected between the two switches. Switch S01 is on top of the machine and is 7 closed only by the book copier platen. Thus in the letter copier mode switch 801 does not close and there I can be any of many different types which are controlled is no need to include it in the redrawn circuit of FIG. 10

(identical to FIG. 4 in the Van Auken et al. application) for the letter copier mode inasmuch as the potential at pin F on the copying machine cannot be extended through switch 801 to any other point in the circuit. However, switch SW-D in the copying machine (FIG. 4) closes when multiple copies of any original (letter, book or microfilm) are being made, as will be described below. Switch SW-D, when closed, connects pin F to pin' C. Referring to FIG. 9, it is seen that in the letter copier mode, the circuit board in the'bridge connects pin Cto'pin D..Referring back FIG. 3, it is seen that pin D is connected to the windings of relays K4 and K5 which operate when multiple copies of a letter are being made. Consequently, the redrawn circuit for the letter copier mode includes switch SW-D.

From this simple example, it becomes apparentthat for an understanding of the Van Auken et al. system operation, it is necessary'to focus not on FIG. 3 incon junction with the circuit connections established by any of the various attachments, but instead on the complete, redrawn circuit which results when a particular attachmentis put in place. The original Van Auken et al. redrawn circuit for the letter bridge is references will be madeto FIG. 3 but rather to the redrawn circuit of FIG. 10, certain of the elements on FIG. 3should be understood. Lines Ll, L2.are connected to a source of power, the circuit path being completed when the machine on-off switch SW4 is closed. Line L2 is extended through switches SW-E, SW-F and respective exposure lamps 1 and 2 back to line L1. The two switches are'shown in FIG. 4 and are closed when cam 95 is rotated by timing motor TMl as will be described below. The closing of the two switches controls energization of the exposure lamps within reflector 25 of FIG. l.v I

The other switches which are shown on FIG. 3 and are included inside the machine are the switches shown on FIGS. 4, 5 and 6, namely, switches SW-A, SW-B, SW-H, SW 0, SW-Q, SW-C and SW-D. The operation of all of these switches will be described below (except switch SW-O which does not enter into the letter to open at the end of the knife stroke.

The only other switches shown in FIG. 3 are switches SlA, S2A, S3A, SIB and S01. These five switches are not inside the machine, but are instead placed on top of the machine. Switch SIA is exposed to view on top of the machine and is the start button which is pushed down to initiate operation of the machine in the book copier mode. The other four switches are not exposed to' view but are operated by the book copier platen as it shuttles back and forth on top of the machine. In the letter copier mode, switch 81A is notoperated and similarly the four platen-operated switches are not operated. All five switches remain open. It is for this reason that these five switches,

various clutches and timing motors. There is no need to develop the potential in the event no attachment is placed on top of the machine. For this reason, arr interlock is provided to prevent the extension of power to the full-wave rectifier in the event no attachment is placed'on the machine. Line L1 is extended directly to one of the input terminals of the rectifier. The other input terminal of the rectifier is connected to pin L. With no attachment on the machine, pin L is floating and no potential is developed across conductors 113, 114. But in the event one of the attachments is placed on the machine, pin L is connected topin K in the attachment. (This connection is made man three attachments.) Pin K is in turn connected to on-off switch SW4 in line L2. Thus, only if one of the attachments is placed on the machine is the potential developed in the nected directly to line L1. The other is connected to pin L, which can be connected to pin K (and line L2) only through one of the attachments. Consequently,

power supply 94 also operates only when one of the attachments is on the machine. The power supply-i's'con nected directly across photocellexciter lamps 19, 20,

In the circuit of FIG. 10, which shows the operative parts of the circuit in the letter copier mode, the photocell detectors are shown simply by boxes SW1, SW2, SW3. For this reason, it is necessary to understand how each of the box switches actuallyoperates. Referring to FIG. 9, one end of photocell 13 included in the letter copier bridge is connected by the circuit board in the letter copier bridge to pin 6 in the machine, while the other end of the photocell is connected to pin 7. Referring to FIG. 3, it is seen that one end of the photocell is connected through resistor R13 to the base of transistor Q1 while the other end of the photocell is connected directly to the emitter of transistor Q1. The photocell functions as a variable potential source. When it is illuminated there is a voltage drop across the photocell and transistor Q1 does not conduct. Relay K1, connected through normally closed contacts [(4-3 to the collector of transistor O1, is thus held de-en ergized. On the other hand, if light does not strike the photocell, the base of transistor Q1 goes positive with respect to the emitter, current flows through the collector circuit of the transistor and relay K1 is operated.

' The positive potential of bus 1 15 is extended through level adjustment potentiometer R1 and resistors R4, R' to the base of transistor Q1. The emitter of transistor O1 is extended directly to negative bus 116. The resistor have values such that with no potential contribution from photocell 13 the potential drop across the base-emitter junction of transistor Q1 is sufficient to cause conduction in the transistor and the operation of relay K1. However, photocell 13 is connected across the baseemitter junction such that the potential developed across the photocell reverse biases the base-emitter junction, that is, the negative terminal of the photocell is connected to the base of transistor Q]. As long as light from lamp 21 is detected by the operating. This operation is depicted in FIG. 10, where the entire lamp and photocell circuit is simply shown as switch SW1 which is normally open. Only when an attachments includes a similar connector,-and when connector 132 is mated with one of the attachment connectors the control circuit which results in unique for the particular attachment. The system operation is considerably different for all three attachments.

Van Auken et al. System Operation in the Letter Copier Mode The letter copier attachment is shown in detail in the Van Auken et al. application. It includes a mechanism for locking it in place on the machine and three rollers which engage rollers 16, 17, 18 on top of the machine.

Adjacent to each roller in the letter bridge is a original document to be copied passes between lamp 21 and photocell 13 does switch SW1 close and current flow through the switch and contacts K4-B to the winding of relay K1. A similar circuit is provided for relays K2 and K3. Referring to FIG. 9, the negative terminal of photocell 14 is connected to pin 8 and the positive terminal is connected .to pin 10. Pin 10 is connected on FIG. 3 to negative bus 116 and pin 8 is connected through resistor R14 to the base of transistor Q2. An identical circuit is provided for photocell 15 and transistor Q3.

At the top of the machine (FIG. 1) are three rollers 16, 17, 18, and one of exciter lamps 19, 20, 21 is adjacent to each roller. The rollers are driven by drive chain 75 (FIG. 2). Between rollers 17 and 18 is scanning window 22, typically, a glass plate.

On one side of the scanning window there is an electrical connector 132 (FIG. 2). This connector has a number of pins which are connected to various parts of the control circuit of the copying machine. Each of the photocell13, 14, 15 (FIG. 1). The photocells are connected by wires to a connector (not shown) which mates with connector 132 on the machine. When this connector is inserted into connector 132 on the machine, it completes the control circuit of FIG. 3 so that it sequences in the letter copier mode. The circuit of the bridge connector is shown in FIG. 9. When the connector mates with connector 132 on top of the copying machine, the circuit of FIG. 3 within the copying machine is completed and results in the circuit shown in FIG. 10.

Two different sequences take place when the machine is operated in the letter copying mode. In the first, only a single copy of an original document is made. In the second, multiple copies of the original document are made. Each of the sequences will be considered individually below.

. Single Copy Operation Referring to FIG. 10, three switches SW1, SW2 and SW3 are shown, the switches being symbolic of the three photocells 13, 14 and 15 and their associated amplifiers in the original transport system. SW1 corresponds to photocell 13, SW2 corresponds to photocell 14 and SW3 corresponds to photocell 15. Each switch is normally open but closes when the original passes under the respective photocell and blocks light from the respective one of light sources 19, 20 and 21.

Before proceeding with a description of the operation of the machine, it is necessary to set forth the meaning of the various notations used on the drawing.

On FIG. 10 there are six relays K1 through K6. Each of I these relays is normally de-energized. Each relay has a number of contact pairs A, B, etc. For example, contacts K2-D are the fourth movable contact pair on relay K2. All of the contacts are shown in their normal positions with all six relays de-energized. In the case of transfer contacts, both pairs are designated alike, e.g., K3-A, with the normally closed connection being shown in the usual manner by a short line drawn at an angle through the contacts symbol.

On FIG. 10 there are also five clutches I( 7, K-8, K-9, K-Il and K-12. Clutch K-l2 is the paper roller clutch which when energized causes copy paper rollers 35 and 36 to operate. Clutch K-12 is shown on FIG. 2 as controlling rotation of roller 35. Clutch K-9 controls forward feed of the original, and when energized causes rollers 16, 17 and 18 to rotate in the directions shown in FIG. 1. Clutch K-7 is the reverse clutch which when energized controls the reverse movement of the original. As seen in FIG. 10 transfer contacts K4-A control the energization of either clutch K-7 or clutch K-9. Clutch K-8 when energized controls movement of tion system) to cam 96 (FIG. 4). v

cam 104 of FIG. 6 in synchronism with original drive chain 75 (FIG. 2). This clutch is operated only during multiple copying. Timer clutch K-11, when operated, clutches chain-driven gear 126).through a gear K-10 is the solenoid which whenenergized operates rotary knife 38 to cut the copy paper. At the end of the knife stroke, switch SW-X is opened. Upon release of the knife, the switch closes once again.

On FIG. 10 there are also two timing motors TM1,

reduc- TM2. When energized, these motors control movements of respective cams 95 (FIG. 4), and 102 and 103 (which comprise selector dial 107 FIG. 5). These cams, as well as cam 104 (FIG. 6), actuate various switches SW-A, SW-B, etc. Each switch has two terminals. With the cams in their normal positions as shown in FIGS. 4-6, some of the switches are open and some are closed. Switch SW-H, for example, is closed,

and as shown in FIG. 10 a connection is made through the two terminals of this switch to the winding of relay K1. Others of the switches such as SW-E are open. As will be described below, rotations of the various cams control the opening. of the normally closed switches, and the closing of the normally open switches.

The circuit 'of FIG. 10 is shown in three parts. The

; various clutches are connected across 90-volt DC buses Y 113, 114. The various relays are connected across 26- volt DC busesllS, 116. The corona and the two timing motors are connected across the AC line. The knife solenoid is connected across line L2 and negative bus With relay K4 de-energized, the normally closed contacts K4-A are closed, forward clutch K-9 is enercurrent flowing through the winding of the'clutchv and the now closed, normally open Kl-B contacts. The corona charging system including a high voltage power source 4 (shown symbolically by numeral 89) is also energized through the now closed K1-C contacts, these contacts connecting the corona charging circuit to line terminal L2. t

At the same'time, timing motor TM1 starts operating with the closing of the Kl-A contacts. The motor circuit is completed from terminal L1 through Kl-A-contacts, and normally closed switch SW-B connected to line terminal L2 Although switch SW-B is bypassed by normally closedcontacts Kl-C, and contacts KS-C and KZ-A, current does not flow through these contacts because contacts Kl-C are open when relay K1 is energized. The operation of motor TM1 starts the turning of cam .95 on FIG. 4. The cam turns counterclockwise and as soon as lobes 95a, 95b move slightly, switches SW -E and SW-F close. Each of these switches is connected in the engineering circuit for one of the two exposure lamps (FIG. 10). In the illustrative embodiment of the invention two such lamps are included in reflector 25 (FIG. 1). Motor TM1 and cam are provided to insure that the exposure lamps remain on for not less than 5 seconds. This is necessary since the lamps have a tendencyto darken on shorter duty cycles. As will become apparent below, cam 95 turns during each copying cycle. If timing motor TM1 is not interrupted, the cam turns this amount within 5 seconds. In the case of long originals, however, the timing motor is interrupted so that the lamps remain energized even longer. I

As soon as lobe 95c moves slightly, switch SW-A closes such that the energizing circuit for timing motor TM1 bypasses contacts Kl-A. Thus, even after relay' -K1 releases, the timing motor can still operate. The

motor continues to run until lobe 95b opens switch SW-B. Unless relays K1 and K2 are released at this time and contacts Kl-C andK2-A are closed, the energizing circuit for TM 1 is broken.

With the closing of contacts Kl -B, timer clutch,

K-ll is energized. Cam 96 starts to turn counterclockwise (driven by chain 75) and insures a cut copy length of. not less than 8 inches. Provided that the length of the original is equal to or greater than 8 inches, the actual length of the cut copy will be identical with that of the original. Otherwise, a minimum length of 8- inches is cut. The 8-inch minimum is to insure that the cutcopy sheet has a sufficient length so as to at all times be driven by rollers in the copy transport section. Otherwise, if the cut copy is too short it may be trapped in the machine.

Although the original energizing current for relay K1- flows through switch SW1, relay K1 remains energized.

if switch SW1 opens before 8 inches of copy paper have been fed from the roll because contacts Kl-D close when the relay operates and current flows through these contacts and normally closed switch SW-H. Even if switch SW-l opens, current flows through contacts Kl -D, diode CR16 and switch SW-H.

The purpose of this circuit is to insure the minimum copy length of 8 inches. By the time cam 96 turns sufficiently to open switch SW-H, at least 8 inches of copy paper have been fed into the copy transport system. (Angle d3 in FIG. 7 corresponds to 8 inches of copy paper feed.) Relay Kl cannot release before this .minimum feedhas occurred, and since knife solenoid K-10 cannot operate until relay K1 releases, the

minimum length cut copy sheet is 8 inches. Only after switch SW-I-I opens can relay K1 release, and only then does the opening of switch SW1 control the knife operation. e

With the closing of contacts Kl-D, current flows through them, diode CR12, normally closed switch SW-X and the winding of relay K6. The relay-energizes and'contacts K6B, in the knife solenoid circuit, close. However, the solenoid does not energize becauseno'rmally closed contactsKl-B are open at'this time.

When relay K6 operates, contacts K6A close to bypass contacts K1-D and to thus keep the relay energized even after relay K1 releases.

RelayKl remains energized until the trailing edge of the original clearsswitch SW1 (assuming. that switch SW-I-I has by this time opened). Normally open contacts Kl-B restore to the condition shown in FIG. 10, clutch K-12 releases, rollers 35, 36 stop turning, and no more copy paper is fed from roll 33. Similarly, the

closing of normally closed contacts K1-B completes the energizing circuit for knife solenoid K-10. (The energizing current is a half-wave rectified signal since the knife solenoid is connected across AC line L2 and DC bus 114.) Rotary knife 38 rotates in the counterclockwise direction (FIG. 1) and the copy sheet is cut from the copy paper roll. At the end of the knife stroke, switch SW-X opens and relay K6 releases. Contacts K6-B open, solenoid K-lO release and the knife restores. Although switch SW-X closes once again, relay K6 does not re-energize because by this time both contacts Kl-D and K6-A are open. Diode CR10 is provided across the knife solenoid to suppress the large transient which could otherwise develop when contacts K6-B open.

The release of relay K1 thus controls both the stopping of the paper roll feed and the operation of the knife. This could present a problem if the feed stops before the knife operates (the copy paper transport system would continue to draw paper while no more could be fed past rollers 35, 36) were the following corrective measure not taken. The forward edge of the copy paper, when it is first fed over rotary knife 38, continues to move upward until it strikes the underside of deflector 66 (FIG. 1). The paper then moves under the deflector toward rollers 39, 40, but the paper bears against the underside of deflector 66, not the upper surface of knife 38. Deflector 66 thus serves as a loop former," establishing some slack in the copy paper between rollers 35, 36 and 39, 40. When rollers 35, 36 stop turning, rollers 39, 40, which continue to rotate, take up the slack. The knife finishes its cut before most of the slack is taken up.

With the release of relay K1 and the opening of normally open contacts Kl-B, timer clutch K-11 also deenergizes. Cam 96 is connected by spring 100 to stop 99. Pin 101 is included on the underside of the cam. As soon as the clutch de-energizes, the spring causes cam 96 to restore in the clockwise direction with the cam stopping when pin 101 hits stop 99. Switch SW-H closes once again when cam 96 returns to its initial position. If by this time relay K6 has not yet released winding of relay K1, while allowing current through I contactsKl-D (when relay Kl first operates) to flow through the switch SWX and the winding of relay K6. As for diode CR16, it is provided to prevent current through switch SW1 from flowing to the winding of relay K6 at the same time that it flows through the winding of relay K1. Transistor O1 (in switch SW1) cannot supply sufficient current to operate both relays. Instead, diode CR16 insures that the closing of switch SW1 directly controls the energization of only relay Kl. It is the subsequent closing of contacts Kl-D which results in the energization of relay K6 (current flowing through diode CR12).

The function of diode CRll is to short out the current in the winding of relay Kl'when the relay releases. This prevents excessive transients from damaging transistor Q1 (part of switch SW1, see FIG. 3). A similar diode is provided for each of relays K2 and K3.

As the original continues to be transported toward the scanning window the leading edge actuates switch SW2 (actually, this occurs before the trailing edge passes switch SW1 and the knife operates). The closing of the switch energizes relay-K2. Contacts K2-B closes to provide an alternate path for the corona charging system through these contacts and normally closed contacts K4-D. Originally, the corona charging current flowed through contacts Kl-C. Even after relay K1 releases, however, the corona charging circuit remains energized as long as relay K2 is operated. This is necessary because were the corona charging system to deenergize with the release of relay K1, the trailing portion of the cut copy sheet would not be charged.

Although normally closed contacts K2-A open with theenergization of relay. K2, this has no effect on the running of timing motor TMI. The motor is held operated by the current flowing through normally closed switch SW-B, and now closed switch SW-A and contacts Kl-A in parallel.

As the original passes the scanning window, the copy paper is exposed. As the original continues to be scanned the leading edge actuates switch SW3.

Although relay K3 energizes, it has no effect during single copy mode operation. Similarly, its release at the end of the cycle has no effect.

As cam continues to rotate eventually one of the camming lobes opens switch SW-B. (As shown in FIG. 4, it is lobe 95b which opens switch SW-B, although it is understood that a different lobe controls this operation during each cycle as the cam makes only one third I releases before relay K2.) Since the trailing edge of the copy paper is now clear of the corona unit further charging is unnecessary. With the release of relay K2, contacts KZ-A close. Since contacts KS-C are always closed during the single copy mode, and normally closed contacts Kl-C restored to their closed position with the release of relay K1, timing motor TMl resumes operating even though switch SW-B is still open. Cam 95 thus resumes its rotation in the counterclockwise direction. Switches SW-E and SW-F are still closed, however, because it is necessary to keep the exposure lamps energized until after the exposure process has been completed.

As soon as cam 95 rotates slightly further in the counterclockwise direction, switch SW-B closes once again to provide an alternate current circuit for timing motor TMl. After cam 95 has rotated one third of a revolution, with the lobes being in the positions shown in FIG. 4 (although each has moved switch SW-A opens. At this time the timing motor turns off because contacts Kl-A are open. Although cam 95 starts turning from its parked position when the trailing edge of the original passes switch SW2 at the forward end of the scanning window, by the time cam 95 has rotated from the parked position through the end of its one-third revolution the original has been completely transported past the scanning window and the copy sheet has completely passed by the copy exposure window. With cam 95 in its initial position (although rotated 120), switches SW-E and SW-F open and the two exposure lamps turn off.

It should be noted that timing motor TMl stops operating and cam 95 is parked when switch SW-B is opened. The operation of the timing motor and the rotation of cam95 resume when the trailing edge of the original passes switch SW2 and relay K2 releases. With a short original it is possible for relay K2 to release even before switch SW-B is opened. In such a case cam 95 is i not parked. However, it requires 5 seconds for cam 95 to rotate 120 and the two exposure lamps thus remain on for at least 5 seconds during each copying cycle. (With an original shorter than the distance between rollers 9 and 8, the original becomes trapped between the rollers and itis necessary to lift the bridge in order to remove the document.)

The original and the copyare deposited in their respective trays as they are passed through the machine. At the end of the process all switches and relays are in the conditions shown in FIGS. 4 and 10 with the exception of cam 95 which has rotated 120. However, since the cam has three symmetrically positioned lobes, as far as the machine operation is concerned the cam is in its initial position;

i In the letter copier mode, original documents can be fed in succession one after the other. This is one of the primary advantages of moving the original document directly (as opposed to'placing it on a glass platen, in which case each original must be removed before another can be placed on theplaten). It is possible that originals may be fed in succession so fast after each other that the trailing edge of the first does not pass switch SW2 before the leading edge of the second passes switch SW1. In such a case, switch SW1 is operated (by the new original) before switch SW2 has been released (by the first original). With both relays operated, contacts Kl-C and KZ-A are open and no current can flow through them to timing motor TMl. However, the timing motor continues to run if lobe 95b has not yet opened switch SW-B, since at this time switch SW-A is also closed. The timing motor con- .is the desired operation the purpose of timing motor TMl isto insure-that the exposure lamps remain energized for at leastS seconds every time they are turned on, and iforiginals are fed into the machine rapidly in succession there is no reason to turn the exposure lamps offduring the sequence- I 3 On the other hand, suppose that the feed rate is slightly slower and that thetrailing edge of the first original releases switch SW2 before the leading edge of the second original operates switch SW1. With relay K2 released, contacts K2-A are closed. When'the second original causes relay K1 to operate, contacts Kl-C open. However, timing motor TM] continues to run if it has not yet reached its park position because both of switch SW-A and SW-B are closed. The timing 7 cannot reach its park position before a normal length original has passed switch SW2. However, it can happen somewhere in the sequence when several originals are fed into the machine in succession.) In such a case, with the release 'of relay K2 (as the trailing edge of the first original passes switch SW2) the timing motor starts to move from its park position. It would appear that the timing motor would complete its cycle and the exposure lamps would turn off while the second I switch opens. The timing motor simply continues to run and enters into a new cycle. Of course, when the timing motor completes its first cycle, switches SW-E andv SW-F open and the two exposure lamps turn off. Were the original document to be within the scanning window at this time, there would be a portion of 'it which would not be fully imaged on the copy during the brief intervalthat the two exposure lamps turn off as cam 95 finishes a'first one-third revolution'and starts another. However, the time required for one of thelobes on cam 95 to move from the position at which'switch SW-B is open to the position at which switch SW-A opens is less than the time required for an original document to be transported from switch SW1 to the scanning window. Consequently, in the event the timing motor has moved past its'park position when a neworiginal is fed into the machine (in which case the timing motor finishes the cycle in progress and enters into a new cycle), the ex} posure lamps flicker off mementarily before the original document reaches the scanning window there is no interruption in the scanning of the original.

It should be noted that in the single cycle sequence,

switch SW-D is open. Consequently, relays K4 and'KS do not energize. Similarly switch SW-C is open, and since contacts K4-D remain open as we'll, timing motor TM2, does not runyRelays K4 and K5 and timing motor TM2, operate only during the multiple copy sequence.

Multiple Copy Operation The number of copies made is selected by the operator. The outer edge of the multiple copy selector dial 107 (FIG. 5) is sequentially numbered in sixteen equal graduations, starting with l and progressing in the counterclockwise direction up to 16 The normal or single copy mode position of the multiple copy selector dial is that in which the numerically designated position of 1 is as shown in FIG. 5. If the dial is in the normal position the machine operates in the single copy made.

To select any other number of copies, the dial is turned until the desired number is in the 12 oclock position. The dial can be rotated or changed at any time during the copying cycle.

During each reverse travel of the original, the dial is rotated one position in the counterclockwise direction by timing motor TM2. This counting down or decrementing of the selector dial provides a visual indication of the number of copies which must yet be made. If the selector is not changed by the operator, the decrementing continues until the dial is in the single copy mode position of FIG. 5. At this time, the original is scanned for the last time after. which it is deposited in the original receiving tray just as it is during the single copy mode.

In the multiple copy operation, the functional sequence is the same as that of the single copy operation except that when the leading edge of the original actuates switch SW3 during thefirst scan cycle, a series of control circuits are. activated. These control circuits reverse the normal travel of the original transport system when the trailing edge of the original clears switch SW3. The original is reversed at high speed. The control circuits also prevent the machine from making a copy while the original is being reversed.

When the leading edge of the original clearsswitch SW2 during high speed reverse, the transport system is again normalized so that the original is transported in the forward direction to be scanned once again. This action is repeated until the multiple copy selector dial is decremented to the 1 position at which time the last scan begins with the machine operating in the single copy mode. The multiple copy selector dial has two camming surfaces 102 and 103. Camming surface 102 has sixteen detent positions equally spaced around the circumference of the cam. The actuating arm for switch SW-C rides on the camming surface. When the actuating arm is on a high portion of the camming surface (between detents) switch SW-C is closed. Each time camming surface 102 is rotated the switch actuat-- ingarm drops into a detent and switch SW-C opens. When the timing motor TM2 is first energized camming surface 102 starts to rotate in the counterclockwise direction. The actuating arm of switch SW-C moves to a high point on camming surface 102 to close the switch. The control circuit that initially starts the timmotor TM2 stops operating.

Camming surface 103 has only one detent. The detent is located at a position such that it will permit the actuating arm of switch SW-D which rides on the camming surface to be in the detent only when themultiple copy selector dialis in the single copy mode posi-' tion. When the actuating arm is in the detent the switch is open. his switch SW-D which controls the multiple copy mode sequencing circuits. When the selector dial is manually rotated to a position representing the number of copies desired, both surfaces of cams 102 and 103 are rotated. With switch SW-D closed the multiple copying operation ensues. But as the selector dial is decremented, switch SW-D opens when the numeral 1" on the dial is in the 12 oclock" position. After the original is reverse transported for the last time, the last of the required number of copies is made in the same way that a single copy is made.

Up to the point when switch SW3 is first energized by the leading edge of the original the operation in the multiple copy mode is the same as that in the single copy mode. With the energization of switch SW3 and the operation of relay K3, contacts K3-B close to energize relay K5. Current flows through contacts K3-B, the relay coil, and switch SW-D, switch SW-D being closed by camming surface l03'when more than one copy is being made.

' When contacts KS-D close, current flows through the energizing coil of multiple copy clutch K-8. The operation of this clutch couples cam 104 (FIG. 6.) to drive chain (FIG. 2). Cam 104 thus rotates in the forward (counterclockwise) direction as shown in FIG. 6. (Gearing, not shown, is provided to gear down the speed of cam 104 with respect to the drive chain spee'd. Cam 104 makes less than a single revolution even for a long original.) Switch SW-Q is normally closed. As cam 104 continues to rotate in the forward direction, switch SW-Q opens in the energizing circuit for relay Kl. However, relay K1 remains energized. Although after 8 inches of copy paper have been fed into the machine switch SW-H is opened by cam 96, relay K1 remains energized by the current flowing through normally closed contacts K4-B and switch SW1 until the trailing edge of the original clears the switch.

When relay K5 first energizes, contacts KS-C open. It will be recalled that in the single copy mode timing motor TMl first operates when relay K1 is energized and contacts K1-A close. The timing motor continues to operate until switch SW-B opens at which time the timing motor is parked. When relay K2 releases and contacts K2-A close (contacts K1C havingclosed earlier), the timing motor continues to operate until cam has turned through its one-third revolution. However, with relay K5 operated and contacts K5-C open in'the multiple copy mode, the timing motor cannot resume operating when relay K2 releases and contacts K2-A close. Consequently, the timing motor remains parked throughout the multiple copy mode. Switches Sw-E and SW-F remain closed and the two exposure lamps remain operated throughout the multiple copy cycle. It is only when the last copy is being made and relay K5 is released because switch SW-D is open that the last release of relay K2 allows timing motor TMl to resume operation. Thus, even in the multiple copy mode cam 95 turns through only during the entire cycle.

With the leading edge of the original at switch SW3, relays K1, K2, K3 and K5 are energized, the corona circuit is still energized through contacts Kl-C, and

through the alternate circuit including contacts K2-B and K4-D, and the copy paper roll clutch K-l2 is still energized through normally open (now closed) contacts Kl-B. The exposure lamp timing motor TMl becomes parked as soon as cam 95 has rotated a sufficient amount to open switch SW-B. Timer clutch K-1 1 is still energized since normally open contacts Kl-B are closed. Assuming that the length of the original is greater than 8 inches, switch SW-H is open; Cam 104 continues to rotate in the forward direction.

The scanning and exposure process continues until the trailing edge of the original clears switch SW1 and relay K1 ale-energizes. When normally open contacts K1 13 open, copy paper roller clutch K-12 tie-energizes to stop the copy paper feed. At the same time knife solenoid K- operates to cut the copy paper 'to the length of the original. Since normally open contacts Kl-B are now open, timer clutch K-ll de-energizes and spring 100 returns cam 96 to the initial position. Relay K6releases with the opening of switch SWX and this in turn causes the knife to restore.

With short originals, relay K1 releases before relay K5 operates since the trailing edge of the original passes switch SW1 before the leading edge reaches switch SW3. The operation is the same, however, except that relay K1 does not de-energize until switch SW-H opens after a minimum length of 8 inches has been fed from the copy paper roll.

Although relay K1 is de-energized and contacts Kl-C areopen, contacts K243 and K4-D are still closed so that the corona charging system is still energ ized. Eventually the trailing edge of the original passes switch SW2 permitting relay- K2.to de-energize. With the opening of contacts K2-C the corona system is deenergized. Originally, relay K5 was energized by the current flowing-through contacts K3-B. As will be seen below, relay'K3 soon releases. However, with relay K2 tie-energized, contacts KZ-D are in their normal closed The copy is then deposited in the copy receiving tray.

When the trailing edge of the original clears switch SW3, rel'ay K3 .de-energizes. While relay K3 was energized, normally closed contacts K3-A were open and normally open contacts K3-A were closed. Since contacts K4 C were open relay. K4 could not operate.

However, when normally closed contacts K3-.A close,

relay K4 operatessince at this time contacts K5-B are closed. With the energization of operations take place. x 1

In the single copy mode, forward clutch K-9 is operated. by current'flowing through normally closed contacts K4-A. to control. the forward feed of the original. Similarly, in the multiple copy mode relay K4 is initially de-energized and the original is fed in the forward direction with the energization of clutch K-9. But as soon as relay K4 energizes, normally open contacts K4-A close, and normally closed contacts'K4-A open. Forward clutch K-9 de-energizes andreverse clutch K-7'energizes. At this time the original is fed in the reverse direction through the machine. As described above in connection with FIG. 2, the reverse feed is faster than the forwardffeed.

Originally, contacts K4,'D j and ,K3-l), and switch SWC were open so that timing motor TM2 could not.

operate. As soon as the trailing edge of the original passes switch SW3, relay K3 releases and contacts K'3-D close. Since relay K4 operates at the same time relay K4 a number of v and contacts K4-D close, current flows through these contacts and contacts K3-D to timing motor TM2. The timing motor thus starts to turn the multiple copy selector dial in the counterclockwise direction. But the original immediately starts its reverse feed through the machine, relay K3 is immediately reenergized and con: tacts K3-D open. By this time cam 107 has not rotated sufficiently such that the actuating arm of switch SW C is on a high portion of camming surface 102. The detents on cam 102 are sufficiently wide to prevent closing of switch SW-C during the short interval that relay K3 is released. With switch SW-C still open when relay K3 re-energizes, timing motor TM2 stops operating. The dial is not decremented at this time.

The first switch to operate during the reverse feed is;

switch SW3 and relay K3 thus energizes. Relay K4 was first operated when relay K3 released and normally closed contacts K3-A closed. Although these contacts now open, relay K4 remains energized by the current flowing through normallyopen contacts K3-A (now closed) and contacts K4-C. In order that contacts K4-C not open during the switching of contacts K3A,

relay K4 is prevented from releasing by current flowing through capacitor C4, this current continuing to'flow until the normally open contacts K3-A close. Relay K5 was originally operated with the energization of relay K3 and the closing of contacts K3-B. Subsequently, the I relay was alternately energized with the release of relay K2 and the closing of contacts K2-D. At the end of the forward feed, contacts K3-B opened with the release of relay K3 but the alternate energizing path' held relay K5 operated. With the closing of contacts K3-B at the start of the reverse feed, relay- K5 is held onby currents through both paths. I

The original continues to travel inits reverse direction. Withrelay Kl de-energized and normally open contactsKl-B open clutch K'l2 is not operated so there is no copy paper feed, and clutch K-11 is not operated so cam'96 does not rotate. Relay K5 is still energized and contacts KS-D are still closed, multiple its reverse direction (clockwise). The cam, which at the end of the forward feed is in a position such as that shown by the numeral 106 in FIG. 6 (the exact position depends on the length of theYoriginal),-starts moving toward its original position adjacent step 105.

The original continues to be reverse transported and cam 104 continues to be restored. The trailing edge of the-original actuates switch SW2 whichresults in'the energization of relay K2. Although contacts K2-D open, relay K5 is held operated through'conta'cts' K3 B. Relay K4 is now held operated through its own contacts K4-C, and both contacts K3-A and K2-C. The trailing edge of the original then actuates switch SW1. This has no effect on relay Kl, however, since switch SW-'Q is open, and since relay K4 is energized normally closed contacts K443 are open as well. (It should be noted that switch SWlis bypassed anyway by normally open contacts K4-B (now closed), which condition similarly cannot control the energizatio'nof [relay Kl.) Even'. 

1. A copying machine comprising a scanning window, means for transporting an original document to be copied in forward and reverse directions past said scanning window, an exposure window, means for transporting copy paper past said exposure window in synchronism with the forward movement of said original past said scanning window, means for scanning said original at said scanning window and in response thereto for exposing said copy paper at said exposure window, first means past one edge of said scanning window responsive, when multiple copies of an original are to be made, for sensing the trailing edge of said original as it moves in the forward direction, means responsive to the operation of said first sensing means for controlling the transport of said original in the reverse direction past said scanning window, second means before the opposite edge of said scanning window for sensing the leading edge of said original as it moves in the reverse direction, means responsive to the operation of said second sensing means for controlling the transport of said original in the forward direction past said scanning window, and means responsive to the sensing by said first sensing means of the leading edge of said original as it moves in the reverse direction for initiating the operation of said copy paper transporting means.
 2. A copying machine in accordance with claim 1 further including third means forward of said second sensing means in the forward direction of movement of an original responsive to the insertion in the machine of an original document to be copies for sensing the leading edge thereof, and means responsive to the operation of said third sensing means for initiating the operation of said copy paper transporting means, said original being reverse transported, when multiple copies of it are to be made, to a position at which its leading edge is somewhat between said third sensing means and the forward edge of said scanning window when its movement is switched from the reverse direction to the forward direction.
 3. A copying machine in accordance with claim 2 further including an adjustable timing circuit for selectively delaying the changing of movement of an original from the reverse direction to the forward direction responsive to the operation of said second sensing means.
 4. A copying machine in accordance with claim 3 wherein said transporting means moves said original at a greater speed in the reverse direction than in the forward direction, and said delay means is adjusted such that the ratio of the distance between said first sensing means and said position to the distance from the leading edge of the copy paper prior to its movement to a point in the copy paper path of movement where said copy paper becomEs synchronized to forward movement of said original is equal to the ratio of the reverse speed of said original to the forward speed of said original.
 5. A copying machine in accordance with claim 4 wherein said first, second, and third sensing means are light-responsive detectors.
 6. A copying machine in accordance with claim 5 wherein said forward transport controlling means includes a relay having a winding which is normally energized just prior to the operation of said second sensing means, the sensing of the leading edge of said original as it moves in the reverse direction by said second sensing means causing said relay to become de-energized, and said delay means is operative to control the flow of current through said winding after the operation of said second sensing means to delay the de-energization of said relay.
 7. A copying machine in accordance with claim 1 further including an adjustable timing circuit for selectively delaying the changing of movement of an original from the reverse direction to the forward direction responsive to the operation of said second sensing means.
 8. A copying machine in accordance with claim 7 wherein said transporting means moves said original at a greater speed in the reverse direction than in the forward direction, said original being reverse transported, when multiple copies of it are to be made, to a position at which its leading edge is between said third sensing means and the forward edge of said scanning window when its movement is switched from the reverse direction to the forward direction, and said delay means is adjusted such that the ratio of the distance between said first sensing means and said position to the distance from the leading edge of the copy paper prior to its movement to a point in the copy paper path of movement where said copy paper become synchronized to forward movement of said original is equal to the ratio of the reverse speed of said original to the forward speed of said original.
 9. A copying machine in accordance with claim 8 wherein said first and second sensing means are light-responsive detectors.
 10. A copying machine in accordance with claim 9 wherein said forward transport controlling means includes a relay having a winding which is normally energized just prior to the operation of said second sensing means, the sensing of the leading edge of said original as it moves in the reverse direction by said second sensing means causing said relay to become de-energized, and said delay means is operative to control the flow of current through said winding after the operation of said second sensing means to delay the de-energization of said relay.
 11. A copying machine in accordance with claim 1 wherein said transporting means moves said original at a greater speed in the reverse direction than in the forward direction, said original being reverse transported, when multiple copies of it are to be made, to a position at which leading edge is between said third sensing means and the forward edge of said scanning window when its movement is switch from the reverse direction to the forward direction, and the ratio of the distance between said first sensing means and said position to the distance from the leading edge of the copy paper prior to its movement to a point in the copy paper path of movement where said copy paper become synchronized to forward movement of said original is equal to the ratio of the reverse speed of said original to the forward speed of said original.
 12. A copying machine in accordance with claim 11 wherein said first and second sensing means are light-responsive detectors.
 13. A copying machine in accordance with claim 12 wherein said forward transport controlling means includes a relay having a winding which is normally energized just prior to the operation of said second sensing means, and the sensing of the leading edge of said original as it moves in the reverse direction by said second sensing means causes said relay to become de-energized, and further including delay means operative to control the flow of current through said winding after the operation of said second sensing means to delay the de-energization of said relay.
 14. A copying machine in accordance with claim 1 wherein said first and second sensing means are light-responsive detectors.
 15. A copying machine in accordance with claim 14 wherein said forward transport controlling means includes a relay having a winding which is normally energized just prior to the operation of said second sensing means, and the sensing of the leading edge of said original as it moves in the reverse direction by second sensing means causes said relay to become de-energized, and further including delay means operative to control the flow of current through said winding after the operation of said second sensing means to delay the de-energization of said relay.
 16. A copying machine in accordance with claim 1 wherein said forward transport controlling means includes a relay having a winding which is normally energized just prior to the operation of said second sensing means, and the sensing of the leading edge of said original as it moves in the reverse direction by said second sensing means causes said relay to become de-energized, and further including delay means operative to control the flow of current through said winding after the operation of said second sensing means to delay the de-energization of said relay.
 17. A copying machine in accordance with claim 16 wherein said delay means is a capacitor coupled to said relay winding.
 18. A copying machine comprising a scanning window; means for controlling the transport of an original to be copied in the forward direction past said scanning window; means for controlling the transport of said original in the reverse direction past said scanning window; an exposure window; means for transporting copy paper past said exposure window; first means responsive to the trailing edge of said original passing thereby in the forward direction for governing the de-energization of said forward transport controlling means and the energization of said reverse transport controlling means, and responsive to the leading edge of said original passing thereby in the reverse direction for initiating the transport of said copy paper by said copy paper transporting means; second means for governing the de-energization of said reverse transport controlling means and the energization of said forward transport controlling means at a time when forward movement of said original will cause it to be in synchronization with movement of said copy paper; and third means responsive to an original being first inserted in the machine and its leading edge passing thereby for initiating the transport of copy paper by said copy paper transporting means at a time such that the leading edge of said original within said scanning window is in synchronization with the leading edge of said copy paper within said exposure window.
 19. A copying machine in accordance with claim 18 wherein said copy paper is fed from a roll toward said exposure window at the speed of said original in the forward direction, and means for cutting a sheet of copy paper from said roll and terminating further feed from said roll responsive to the trailing edge of an original passing said third means in the forward direction
 20. A copying machine in accordance with claim 19 wherein said third means is positioned on one side of said scanning window, said first means is positioned on the other side of said scanning window, and said second means is responsive to the leading edge of said original passing thereby in the reverse direction and is positioned forward of said third means.
 21. A copying machine in accordance with claim 20 further including means for selectively delaying de-energization of said reverse transport controlling means and the energization of said forward transport controlling means for a predetermined time interval after the operation of said second meAns.
 22. A copying machine in accordance with claim 21 wherein said first, second and third means are light-responsive detectors.
 23. A copying machine in accordance with claim 22 wherein said forward transport controlling means includes a relay having a winding which is energized as an original passes thereby in the reverse direction, the operation of said second means as the leading edge of said original moves thereby in the reverse direction causing said relay to become de-energized, and said delaying means is operative to control the flow of current through said winding after the operation of said second means to delay the de-energization of said relay.
 24. A copying machine in accordance with claim 18 wherein said third means is positioned on one side of said scanning window, said first means is positioned on the other side of said scanning window, and said second means is responsive to the leading edge of said original passing thereby in the reverse direction and is positioned forward of said third means.
 25. A copying machine in accordance with claim 24 further including means for selectively delaying the de-energization of said reverse transport controlling means and the energization of said forward transport controlling means for a predetermined time interval after the operation of said second means.
 26. A copying machine in accordance with claim 25 wherein said first, second and third means are light-responsive detectors.
 27. A copying machine in accordance with claim 26 wherein said forward transport controlling means includes a relay having a winding which is energized as an original passes thereby in the reverse direction, the operation of said second means as the leading edge of said original moves thereby in the reverse direction causing said relay to become de-energized and said delaying means is operative to control the flow of current through said winding after the operation of said second means to delay the de-energization of said relay.
 28. A copying machine in accordance with claim 18 further including means for selectively delaying the de-energization of said reverse transport controlling means and the energization of said forward transport controlling means for a predetermined time interval after the operation of said second means.
 29. A copying machine in accordance with claim 28 wherein said first, second and third means are light-responsive detectors.
 30. A copying machine in accordance with claim 29 wherein said forward transport controlling means includes a relay having a winding which is energized as an original passes thereby in the reverse direction, the operation of said second means as the leading edge of said original moves thereby in the reverse direction causing said relay to become de-energized, and said delaying means is operative to control the flow of current through said winding after the operation of said second means to delay the de-energization of said relay.
 31. A copying machine in accordance with claim 18 wherein said first, second and third means are light-responsive detectors.
 32. A copying machine in accordance with claim 31 wherein said forward transport controlling means includes a relay having a winding which is energized as an original passes thereby in the reverse direction, the operation of said second means as the leading edge of said original moves thereby in the reverse direction causing said relay to become de-energized, and further including delaying means operative to control the flow of current through said winding after the operation of said second means to delay the de-energization of said relay.
 33. A copying machine in accordance with claim 18 wherein said forward transport controlling means includes a relay having a winding which is energized as an original passes thereby in the reverse direction, the operation of said second means as the leading edge of said original moves thereby in the reverse direction causing said relay to become de-energized, and further including deLaying means operative to control the flow of current through said winding after the operation of said second means to delay the de-energization of said relay. 